N-carboxy amino acid anhydrides are useful as intermediate raw materials for synthesis of polypeptides from amino acids.
A large number of production methods for production of the N-carboxy amino acid anhydrides have been publicly known. The inventors of the present invention have recently found that an amino acid carbamate compound obtained from an amino acid or an ester thereof and diphenyl carbonate is useful as a raw material for synthesis of an N-carboxy amino acid anhydride, and have patent-applicated (Patent Document 1).